This disclosure relates generally to methods and apparatus for coupling a riser string to an offshore drilling rig. More specifically, this disclosure relates to methods and apparatus for coupling the auxiliary lines of a riser string to a drilling rig. Still more particularly, this disclosure relates to methods and apparatus that provide connections between the auxiliary lines of a riser that can be automatically repositioned so as to allow other equipment to be moved into and out of the moon pool of the offshore drilling rig.
Offshore drilling rigs utilize drilling risers as the conduit between the drilling equipment at the surface and drilling equipment mounted on the seafloor. The drilling riser is a tubular conduit that serves as an extension of the wellbore from the equipment on the wellhead at the seafloor to the floating drilling rig. Conventional drilling risers include a primary tubular conduit and a plurality of smaller, higher pressure auxiliary conduits that are externally mounted to the primary tubular and provide conduits for choke, kill, and auxiliary fluid communication with the subsea blowout preventers.
At the top of the riser string, these auxiliary conduits end in a terminal fitting that includes a plurality of goosenecks that connect to high pressure flexible hoses that are coupled to stationary piping on the drilling rig. The flexible hoses are necessary to compensate for the relative motion that occurs between the drilling rig and the riser. Conventionally, during riser assembly, the flexible hoses are manually connected to the gooseneck by rig personnel that are often suspended over the moon pool during this process.
Manufacturers have begun to offer gooseneck assemblies that can be connected to the auxiliary lines without manual intervention. These gooseneck assemblies can be coupled to the flexible hoses in a location away from the moon pool and can then be moved into position and coupled to the riser with minimum manual intervention. Once the gooseneck assembly is in position on the riser, the flexible hoses drape into the moon pool.
When other equipment, such as the blowout preventer stack, needs to be moved through or into the moon pool, the flexible hoses often have to be moved out of the way to clear a path through the moon pool area. Conventional methods for moving the flexible hoses include simply pushing the flexible hoses out of the way with the equipment or manually moving the flexible hoses using tugger lines and winches. Each of these methods has drawbacks that can result in damage to equipment and exposing personnel to potential hazards.
Thus, there is a continuing need in the art for methods and apparatus for facilitating the management of flexible hoses within the moon pool that overcome these and other limitations of the prior art.